Method and apparatus for singulating particles in a stream

ABSTRACT

Particles are sorted into paths based on a measurable parameter by forming them into a stream in at least one duct carried on a body rotating around an axis where the duct is shaped so that the particles are accelerated to cause the particles separated into the duct to be aligned one after another in a row in the duct. The parameter of the particles are measured in the aligned stream one after the other and the particles are directed into one of a plurality of paths as determined by the measurement. In one arrangement the body comprises a disk member having a front face facing a supply conduit and the duct lies in a radial plane of the disk member. In one arrangement the measurement of the parameter is carried out by one or more measurement devices either carried on the disk or outside the edge of the disk.

The invention relates to a method singulating particles so that anaction can be carried out on the particles such as for detectingparameters of particles in the stream. This invention can be but is notnecessarily used in a method and apparatus for sorting the particlesafter the singulation. The arrangement described hereinafter isprimarily directed to sorting seeds or kernels based on an opticalassessment of the particle for example to extract diseased seeds; butthis invention can be applied to using any assessment method fordetection of any parameter of the particle and sorting based on thatparameter. Also this invention can be used for carrying out an operationon the particle when singulated for example for coating, sterilizing orsupplementing the particle in the stream.

BACKGROUND OF THE INVENTION

Optical seed sorting machines in general have three subsystems: means tosingulate or separate kernels; means to detect quality characteristicsof kernel; and means to displace kernels with a positive or negativequality characteristic.

The most common singulation method in seed sorters is the waterfallmethod wherein seeds are discharged from a vibrating hopper and areaccelerated by gravity along an inclined plane at a steep angle. Thedisplacement due to gravity is quadratic with time, so a gap opens upbetween kernels that enter the system at slightly different times. Inthe commercial art, the slides are typically more than 1 m long. Seedssingulated by the waterfall method are discharged at random intervalsand have a range of velocities. More deterministic systems use movingbelts, cylinders, or plates with defined kernel positions. In onevariety, kernels are temporarily confined within an indent on a belt orplate by gravity. In another variant, kernels are confined within anindent by centrifugal force. In yet another variant, kernels are engagedby suction to fixed positions on a plate, cylinder or belt.

Kernel properties are typically measured optically, but acoustic methodsare also known in the literature. Optical methods can be classified asimaging and non-imaging. In imaging methods, one or more cameras captureimages in two to four wavelength bands. Strobed illumination istypically used. These methods are subject to problems of synchronizationbetween various measurements and enhancements have been proposed to aidsynchronization. Non-imaging methods measure the collective propertiesof a large portion of a kernel. Examples include near infrared spectraand scattering.

Most prior art uses compressed air to eject kernels. Despite severaltechnical advances, compressed air ejection is inaccurate, has a slowresponse rate, and is not energy efficient. In 2008, a system has beenproposed that uses mechanical levers attached to a rotary voice coilwhich is more accurate and uses 10% of the energy that a compressed airsystem uses. However, the cycle time of a voice coil is comparable tothe activation time for a compressed air ejector.

In one example, the invention herein can be used to detect and removeinfected kernels from grain. Incident light is scattered by the kernelwith an infected kernel reflecting and scattering quantitativelydifferently from a healthy kernel. The amplitude of the reflected andscattered light is measured by a detector, normalized to kernel area,and compared to a threshold value derived from statistical analysis ofseparate samples of known healthy and infected kernels. In the method asdeveloped, when the amplitude is above a threshold value the kernel isconsidered “infected,” when the scattered light falls below thethreshold value, the kernel is considered “healthy.” The threshold canbe set so as to minimize the overall amount of mycotoxin in kernelsdeemed “healthy.” “Infected” kernels are then separated from “healthy”kernels.

Although the invention is described and referred to specifically as itrelates to a method and an apparatus to perform the method to detect andseparate infected grain by comparison of the amplitude of scattered andreflected light, it will be understood that the principles of thisinvention are equally applicable to similar methods, devices, machinesand structures for particle separation of any type. Accordingly, it willbe understood that the invention is not limited to such methods,devices, machines and structures, for infected grain separation.

The invention is particularly applicable to Fusarium head blight whichis endemic in all grain producing regions globally and infects cerealgrains such as wheat. Infection rates vary from a few percent in regionswith a dry climate to over 50% in regions with a moist climate. Theseverity of infection ranges from less than 1% FDK (Fusarium DamagedKernels) to 100% FDK with values between 1% FDK and 5% FDK having thelargest volumes. Mycotoxins associated with infected kernels reduce thecommercial value. 1% infected kernels generally equilibrates to 1 partper million of mycotoxin, the current Canadian maximum for food, whilethe EU has a maximum of % part per million. Grain with more than 3% FDKis usually steeply discounted. As infected wheat has little or nocommercial value, effective removal of mycotoxin has significanteconomic value. Wheat is graded in steps of maximum fusarium infectedkernels at 0.25%, 0.5%, 1%, 1.5%, 2%, 5%, not all steps are present foreach type of wheat, with increasing discounts at higher infection. InCanada more than 5% is graded “fusarium damage,” more than 10%“commercial salvage,” which depending on market conditions may be soldat very deep discount, or not at all. Mycotoxin content is currentlyreduced either by sieving the kernels as healthy kernels are larger thaninfected kernels, or by abrading (removing the kernel surface where thetoxin is concentrated) at milling. As a rule of thumb, milling reducesmycotoxin by half at 2 ppm (to 1 ppm) by removing the outer layer of thekernel. Gravity tables are also used to separate kernels by density.Kernels are suspended in an air stream. Denser healthy kernels sink andless dense kernels float to the top. Empirically, sieving and gravitytables remove about 40% of FDK.

SUMMARY OF THE INVENTION

According to the invention there is provided a method for singulatingparticles comprising:

providing a supply of massed particles in a supply conduit;

rotating a rotary body around an axis;

the rotary body defining at least one duct extending from an inner endadjacent the axis outwardly to an outer end spaced at a greater radialdistance outwardly from the axis than the inner end;

feeding the massed particles at the inner end of said at least one duct;

the inner end being arranged in an array adjacent the axis so that thesupply conduit acts to deposit the particles at the inner end of said atleast one duct for entry of the particles into the inner low velocityend and for separation of the stream of particles in the conduit intoseparate ones of said at least one duct;

said at least one duct being shaped and arranged so that the particlesare accelerated as they pass from the inner end to the outer end so asto cause the particles separated into said at least one duct to bealigned one after another in a row in the duct as they move toward theouter end.

In many cases the method includes carrying out an operation on thesingulated particles while they remain singulated. That operation caninclude merely looking at or counting the singulated particles. Howeverthe singulation is particularly effective for processing the singulatedparticles such as by coating, inoculating, sterilizing. In other casesthe operation can include carrying out analysis or assessment of theparticles. However in other cases the particles may be used in thesingulated state such as in seeding where the singulation can be carriedout at high speed into separate ducts for high speed seeding operations.While the system can be effective for a single duct to generate a highspeed stream of singulated particles, in many cases there is provided aplurality of ducts arranged in an array around the center feed conduit.

The method defined above can be used in a method for detecting at leastone measurable parameter of a stream of particles comprising:

carrying particles in a stream of particles in a supply conduit;

rotating a rotary body around an axis;

the rotary body defining at least one duct extending from an inner endadjacent the axis outwardly to an outer end spaced at a greater radialdistance outwardly from the axis than the inner end;

the inner end being arranged adjacent the axis so that the supplyconduit acts to deposit the particles at the inner end of said at leastone duct for entry of the particles into the inner end;

said at least one duct being shaped and arranged so that the particlesare accelerated as they pass from the inner end to the outer end so asto cause the particles separated into the duct to be aligned one afteranother in a row in the duct as they move toward the outer end;

and for each of said at least one duct, measuring said at least oneparameter of the particles.

In some cases the method is provided for sorting the particles so that,for each of the ducts, the particles are directed into one of aplurality of paths as determined by the measurement of the parameter.However the measurement of the parameter or parameters, which isobtained more effectively in view of the increased degree of singulationof the particles using the arrangement herein, can be used for otherpurposes.

The arrangement defined above therefore can provide an advantage thatthe increased velocity obtained by rotation of the body together withthe increased acceleration of the particles on the body better separateseach particle from the next for detection of the parameter. In additionthe increased velocity of the particles can be used to increase thethroughput of the system as the detection or measurement of theparameter can be carried out more quickly.

In one arrangement the measurement of the parameters is carried outwhile the particles are in the duct. This has the advantage that thelocation of the particles is more clear and defined since it iscontrolled by the rotation of the body and the position of the duct. Inview of the more accurate location of the particle, the measurement ofthe parameter can in many cases be carried out more effectively.

In this case preferably the measurement of the parameter is carried outby a measurement device carried on the rotary body. In this way themeasurement device is located at a specific position relative to theduct and relative therefore to the particles. This can simplify theoperation of the measurement device since it can be focused moreaccurately on a specific location. In this case each duct may includeone or more separate measurement devices dedicated to the measurement ofthe particles flowing through that duct. That is each particle whenmoving along a duct can pass a number of sensors or measurement devices,which may be aligned in a row, where each detects a different parameterof the particle to enable a better assessment of the particle to bemade. However in some cases a single sensor can provide all of therequired information.

Preferably, at least a portion of the duct proximate to the measurementdevices is comprised of a transparent material. The provision of aportion of the duct as transparent allows the measurement to be carriedout through the transparent section while the duct remains of a constantshape to continue to control movement of the particle.

In one arrangement, the walls of the ducts or the ducts themselves aresegmented with one or more gaps between segments. One or moremeasurement devices are located proximate to the gaps to measuredifferent parameters of the particle with a view unobstructed by thewalls of the ducts. Where the duct itself is divided into separatedsegments, each segment is preferably arranged along the path of the ductsubstantially parallel to the average velocity vector of the particlesat the location of said segment to minimize perturbation of particleflow along the duct. The particle can thus be operated upon using any ofthe techniques described herein while it is in the gap.

In another arrangement, the separation of the particles can be carriedout using electrostatic forces where the particles are chargeddifferentially according to selected parameters and then passed througha field so that the differential charging causes the particles to divertto different paths. Typically, an arrangement is provided whichgenerates an equal charge on each particle so that particles ofdifferent mass are separated by passing those particles through a fieldwhich acts differentially on the particles based on their differentmasses since each particle has a different or unique charge per unitmass.

In an alternative arrangement the measurement of the parameters can becarried out by a plurality of measurement devices located in an annularzone surrounding the outer ends of the ducts so that the measurement iscarried out after the particles are released from the ducts. This hasthe advantage that the measurement devices are or can be stationary inspace with only the ducts on the rotary body rotating. This has thedisadvantage that the specific location of the particle can vary over alarger range thus reducing the ability of the measuring device to bespecifically focused. The measuring device therefore may need to carryout measurements in a wider area to accurately carry out themeasurements wherever the particle is located in that area.

Preferably each measurement device is associated with a respective oneof a plurality of separation devices each arranged for directingrespective particles into one of a plurality of paths as determined bythe measurement of the parameter by the associated measurement device.That is, each particle is detected and measured by the measurementdevice and that measurement is used to activate an associated separationdevice which diverts the particle into one of a plurality of separatepaths depending upon its parameter.

In a preferred arrangement the measurement of the parameters is carriedout by a plurality of measurement devices where the number of devices isequal to the number of ducts or there may be more than one device foreach duct. That is each particle in each duct is independently measuredusing a separate measuring device for each of the ducts. However it willbe appreciated that the ducts can be arranged to direct particles tomeasurement devices which are associated with a plurality of the ducts,providing the particles are properly spaced each from the next andproperly directed. The measuring devices can include a plurality ofseparate measuring components, for example, X-ray, UV, visible,scattering, infrared, microwave and acoustic detectors.

In one arrangement the measurement device or devices and the particleseparation device are both located on the rotary body. This ensures thatthe location of the particle is more specifically defined but requiresthat the operating components be mounted for rotation with the body.

In another arrangement there is provided an array of stationary particleseparation devices arranged around the rotary body so that particlesreleased from the outer ends of the ducts are operated upon by one ofthe separating devices depending upon an angular position of release ofthe particle from the outer ends of the ducts.

That is the particles can be unguided as they pass from the outer end ofthe ducts to the array of separating devices along a trajectorydetermined by the angular velocity of the rotary body and the directionof the duct at the outer end and wherein the associated detectingdevices are located relative to the separating device to act on theparticle in its trajectory.

In this arrangement there can be provided a guide member at the outerend of each duct which is operable for changing the trajectory as theparticle is released from the rotary body.

Preferably each separating device is associated with a guide channelinto which the particle enters when it is released from the outer endand the associated detecting device acts on the particle while it is inin the guide channel.

In one preferred arrangement the rotary body comprises a disk having afront face facing the supply conduit and the ducts lie in a radial planeof the disk and extend outwardly from the axis to a periphery of thedisk. However other shapes and arrangements of the rotary body can beused. For example the body can be 3-dimensional with the channels orducts also having a component extending in the Z-direction along theaxis of rotation. This can be used to change the acceleration forces onthe particles in the ducts as the particles move radially outwardly. Inone preferred arrangement the shaping of the ducts is such that there isa first acceleration zone to accelerate the particles to cause therequired separation which is then followed by a zone of no netacceleration. In a third section there may be a deceleration zone so asslow the particles as they approach the separation system or thecollection system to reduce impact loads either during separation or asthe particles are halted to a collection system. These zones can beobtained using shaping of the ducts in a 2-dimensional structure or in a3-dimensional structure.

In the second zone, the path of the duct is arranged so that theinertial forces are balanced, on average, by friction so there is no netacceleration and the kernel spacing remains nearly constant. Theadvantage of a nearly constant velocity zone is that there is more timeto make kernel measurements.

In some cases it may be advantageous to decrease particle velocity(deceleration) prior to separation or sorting, or after the action hasbeen carried out, to minimize or eliminate damage from high velocityimpacts. The magnitude of the decrease is limited by the requirementthat the separating mechanism acting on kernel n needs time to return toa neutral position before kernel n+1 arrives. The gap between kernelscan be reduced after measurement to the time for an ejection cycle. Thepurpose of the deceleration is for use of the system with particleswhich can be damaged at high velocity impacts. The need for decelerationmust be balanced with the need for the degree of singulation requiredfor the action and the need for the maximum throughput.

The velocity of a particle can be held nearly constant, after theacceleration to obtain the required singulation, by adjusting the rateof radial displacement along the path of a duct to balance frictionalforces with inertial (centrifugal and Coriolis) forces.

Where the rotary body is a disk, preferably the ducts form channels withan open face facing toward the supply conduit. However otherarrangements can be used in which the disk is not necessarily a completesolid structure but can be provided simply by those parts of a diskshaped body that are necessary to provide the ducts or conduits throughwhich the particles pass. In one example the structure can be providedby a hub and spoke construction in which the particles are fed at thehub into ducts each defined by a respective one of the spokes. Whiletypically the structure includes as many ducts as can be possibly formedinto the structure to maximize the flow rate of the system by maximizingthe number of ducts, in some cases the structure may include a verylimited number of the ducts for example only one or two where highthroughput is not required.

Preferably the ducts are curved so that the outer end is angularlyretarded relative to the inner end. This shape typically follows closelythe path of the particle as it is accelerated under centrifugal forceand Coriolis force so that the particle can travel along the pathwithout excessive friction against the sides of the duct.

Preferably the ducts are arranged immediately side by side at the innerends adjacent the axis so that the feed conduit deposits the particlesin the manner which separates the particles directly into the inner endsof the ducts, with the ducts increasing in spacing toward the outer endsas the ducts move toward areas of increased diameter on the rotary body.

In order to maximize the number of ducts, at the outer end of the ducts,preferably the ducts can include branches which separate the stream ofparticles into separate branch ducts to increase the number of outletsrelative to the number of inlets, thus maximizing the number of outletsat the outer edge of the rotary body.

In another optional arrangement the ducts can be stacked one on top ofanother at the inner ends to maximize the number of inlets and arearranged in a common radial plane at the outer ends so that all of theoutlets lie side by side in the radial plane at the outer edge of therotary body.

In another optional arrangement each duct fed by the central feedconduit termed ‘parent duct’ may have one or more subsidiary ductstermed ‘child duct’. Each child duct is fed by either the parent duct oranother child duct. The child ducts run substantially parallel to theparent duct. Particles pass from a first duct into a second duct throughone or more passages in the wall(s) of the first duct that exert forceon the particle. Each passage in the first duct is shaped to allowparticles smaller than a threshold dimension to pass into the secondduct. Particles larger than the threshold value are retained by thefirst duct. The passage functions as a size filter so that the dischargeend of the parent duct conveys the largest particles and each subsequentchild duct conveys progressively smaller particles. The child ducts maybe associated with detectors and ejectors or other actions on theparticles therein or may simply convey unwanted particles to a discardbin. In the case of grain kernels, child ducts may be used to conveyless desirable particles such as immature seeds, broken seeds, weedseeds, and dirt.

Preferably the axis of the rotary body is vertical so that the disk liesin a horizontal plane. However other orientations can be used.

Preferably a side wall of each duct against which the particles run isinclined in a direction along the axis so that acceleration forces onthe particles act to move the particles into a common radial plane forrelease from the rotary body. That is the acceleration forces tend tomove the particles axially of the rotary body toward a common axialposition. In this way, even if the particles enter the ducts atpositions spaced along the axis, the shape of the duct brings them allto the same axial location.

In one preferred arrangement, each duct is shaped such that theacceleration causes the particle to move against a wall of the ductwhere the wall is V-shaped to confine the particle to a base of theV-shape. The wall can include a surface which includes rifling forengaging and rotating the particle in the duct. In addition the wall caninclude one or more openings at a location such that components smallerthan the particles are separated from the particles by release throughopenings. Each duct can include an associated second duct parallel tothe duct into which the separated smaller components enter. This can beused in a system where there is a stack of such ducts so that theparticles are separated by size from the first.

In one example each separating device comprises a separating head havinga front edge arranged such that the particles to be separated movetoward the front edge in a stream and an actuator for moving the frontedge between a first position on one side of the stream arranged todirect the particle to a second side of the stream, and a secondposition on a second side of the stream, arranged to direct the particleto said one side of the stream.

In this example preferably the separating head is arranged in a radialplane of the rotating body and the first and second sides are arrangedon respective sides of the radial plane.

In this example preferably the separating head includes inclined guidesurfaces on the first and second sides of the front edge so that theseparating head is generally wedge shaped.

Preferably the actuator is moved by piezo electric members. Howeverother drive forces can be used for example an electromagnetic voicecoil.

Preferably the actuator is mounted in a tube which extends radiallyoutward of the separating head and lies in a radial plane of theseparating head.

In accordance with another important feature of the invention which canbe used independently of other features, each separating devicecomprises a duct portion arranged such that the particles to beseparated move through the duct portion in a stream and an actuator formoving a discharge end of the duct portion between at least two separatepositions arranged to direct the particles to corresponding separatecollection locations.

In this arrangement preferably the discharge end of the duct portion ismoved to said first and second positions which are spaced axially of therotary body. However other movements are possible provided the first andsecond positions allow the required separation into separate locationsor into separate collecting channels.

In this arrangement preferably the duct portion is mounted on the rotarybody for rotation therewith. However the movable duct portion can alsobe used with an embodiment in which the particles are directed into aduct portion after they leave the rotary body where the duct portion ismoved to the separate positions depending upon the measurement thatoccurs.

In some cases the actuator is moved by piezo electric members. Howevermore preferably, in order to provide the amount of force and movementnecessary, the actuator is more typically an electromagnetic voice coil.

In accordance with another important feature of the invention which canbe used independently of other features, each duct preferably includes afirst portion arranged for separating the particles each from the nextby acceleration and a second portion for measuring where the first andsecond portions are arranged such that the particle acceleration in thefirst portion is greater than that in the second portion. The intentionis that in this method the second portion is arranged such that theparticle acceleration in the second portion is low or close to zero tokeep the particles at or close to constant velocity during measuring.

In accordance with another important feature of the invention which canbe used independently of other features, preferably a further portion ofthe duct is provided in which the particle is decelerated to reduce itsvelocity for separation or, after the action has been completed, forcollection of the particles. In this way it is possible to reduce thevelocity of the particles sufficiently to avoid the impact damage,particularly where the particles are larger seeds such as peas or beansor berries which have a high mass and are relatively soft.

In one example the particle can be decelerated by a shape of the furtherportion of the duct which acts to decelerate the particles therein. Thatis the shape of the duct portion is arranged to counter the centrifugalforces accelerating the particle.

In another example the particle can be decelerated by an air streamlocated in the further portion such as by an air nozzle or the like.

In accordance with another important feature of the invention which canbe used independently of other features, the particles when directed canbe engaged by an impact surface which is arranged to impact theparticles while reducing the impact loads thereon. For example theimpact surface includes a resilient material to reduce the impact loadson the particle. However other arrangements such as the shaping of theimpact surface can be used.

In accordance with another important feature of the invention which canbe used independently of other features, there is provided a closuremember for closing off access to one or more of the ducts from thesupply conduit. This can be used in a situation where one or more of theducts is closed off from the supply conduit so that only some of theducts are available to be used when supply of particles from the supplyconduit is low.

This closure feature is also useful to allow continued operation of aunit (at reduced capacity) when a diagnostic test shows that one of moreof the measurement devices or ejectors is malfunctioning allowing thesystem to continue with the properly functioning ducts.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a stream of theparticles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

wherein each separating device comprises:

-   -   a separating head having a front edge lying generally along the        stream so that particles in the stream move toward the front        edge;    -   and an actuator for moving the front edge between a first        position on a first side of the stream, arranged to direct the        particle to a second side of the stream, and a second position        on the second side of the stream, arranged to direct the        particle to the first side of the stream.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a stream of theparticles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

wherein each separating device comprises an actuator for moving aseparating component between a first position arranged to direct theparticle to a first path, and a second position arranged to direct theparticle to a second path;

wherein the actuator is moved by a piezo electric member.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a stream of theparticles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

wherein each separating device comprises a duct portion arranged suchthat the particles to be separated move through the duct portion in astream and an actuator for moving a discharge end of the duct portionbetween at least two separate positions arranged to direct the particlesto corresponding separate collection locations.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a stream of theparticles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

wherein each particle passes through a first portion of a path arrangedfor separating the particles each from the next by acceleration and asecond portion where the first and second portions are arranged suchthat the particle acceleration in the first portion is greater than thatin the second portion.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a stream of theparticles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

and decelerating each particle to reduce its velocity to preventparticle damage.

According to one aspect of the invention there is provided a method forsorting particles comprising:

carrying particles to be sorted in a supply conduit;

forming the particles from the supply conduit into a plurality ofseparate streams of the particles in a row;

locating a particle separating device at the stream operable to directeach particle into one of a plurality of paths as determined byoperation of the separating device;

including closing off access to one or more of the streams from thesupply conduit.

In all of the above aspects, operation of the separating device is basedon a measurement of a parameter of the particle measured in the path.However the separation device can be used in other situations where nomeasurement occurs.

The arrangement herein can include the possibility of measuring aquality parameter of a singulated particle, performing an operation onthe singulated particle, and then measuring a quality parameter afterthe operation to determine a further operation. The cycle of measure andoperate can happen several times. The arrangement herein can alsoinclude the possibility of performing an operation on the singulatedparticle, and then measuring a quality parameter after the operation todetermine a further operation. The cycle of operate and measure canhappen several times. The arrangement herein can also include thepossibility of measuring a quality parameter of a singulated particlewithout an operation step. The arrangement herein can also include thepossibility of performing an operation, or sequence of operations on thesingulated particle without a measurement step.

That is some of the sequential operations can be the separation definedherein. The separation operation may be cascaded in multiple steps. Forexample a first measurement may be used to determine which of two ormore subsequent paths the particle follows. Each path may have distinctfurther operations and measurements. The cycle may be repeated multipletimes to produce a plurality of output steams. However other processescan be carried out in the same system such as coating of a particle orirradiation of a particle for sterilization. Singulation allows accessto all particle surfaces for coating or irradiation. Withoutsingulation, coatings may be inhomogeneous, or bridge between adjacentparticles. Singulation can facilitate a superior coating process.Sterilization by UV radiation, for example is effective only on surfaceswith a direct line of sight between the surface and radiation source.Shaded surfaces are not sterilized so singulation is critical to theeffectiveness of a sterilization process. Each duct therefore may beassociated with a plurality of sequential processes some or all of whichare related to separation and some may relate to other processes on theparticle. Some of the processes may operate on the particle to improve ameasurement step at a subsequent station along the duct. In between someof the processes it may be necessary to decelerate and/or accelerate theparticles.

Thus the invention may be used to control the flow of particles in amulti-step process and to customize the processing of each particlebased on measured parameters. There may be a plurality of detectionsteps and a plurality of operations performed on the particle based onparticle properties measured at each detection step. For example, thefirst step could be to detect and remove foreign material such as chaffand material remaining could flow further down a duct to a seconddetector that measures seed quality parameters. In another example,singulated seeds flowing along a duct may be given different coatings(fertilizer, fungicide, insecticide, pro-biotic, etc.) based on measuredseed parameters. In another example, a dose of radiation, such as anelectromagnetic radiation or a photonic treatment, can be applied to aparticle flowing in a duct and this dose could be applied dependent onmeasured particle parameters. The electromagnetic radiation could beused to bake a natural product (microwave, infrared) or to control thedegree of photo-polymerization in a bead (UV).

The multi-step process can also be carried out using a second rotatingbody which receives the particles from the first, such as an annulardisk surrounding an inner disk which is then able to rotate at adifferent rate.

Sorting is usually done to segregate a heterogeneous feedstock into morehomogeneous bins and then further processing can be done on the morehomogeneous feedstock. Conceptually, the processing step can be done onthe singulated particles.

In cases where a “soft landing” is desired to prevent impact damage tovulnerable particles, the particle may impact a curtain or brush withstrips that can deform on a time scale commensurate with the impactperiod. The curtain may consist of water. In one embodiment a watermeniscus is formed by a bin rotating about a common axis with thesingulating apparatus. In another embodiment, the water curtain is awaterfall surrounding the singulating apparatus. These embodimentsincluding a water curtain are preferred to minimize or eliminate damageto soft fruits such as blueberries or Saskatoons. Alternativearrangements for providing controlled deceleration of fragile particlessuch as berries include surfaces which smoothly and gradually turn theparticles in a vertical direction from the horizontal plane of the ductsso that gravity against the upward moving particles reduces the velocitywith low forces from deceleration. This effect can also be obtained byforming a rotating liquid meniscus in a disk surrounding the ducts sothat the particles turn in the liquid upwardly out of the plane of theducts. It will be appreciated that many particles depending on theirstructure require controlled deceleration either in the duct ordownstream of the duct after the operation, such as measurement andseparation, is complete and before the particles are collected. Variousmethods for the controlled deceleration can be provided and aredescriber herein.

The present invention is not limited to the type or size of particleconcerned and may be operated with different particles or objects to beseparated.

Berry fruits such as Saskatoons and blueberries have a short shelf lifedue to spoilage and need to be processed promptly following harvest.Spoiled and unripened berries are sorted out. The present inventionprovides a means to sort berries faster, which reduces spoilage andpresents the consumer with a higher quality product.

In agriculture, crop yield is optimized by planting a specified numberof seeds per unit area. Not all seeds produce viable plants. Extra seedsare planted to compensate for seeds that fail to germinate or fail toproduce vigorous plants. The present invention can be used, typically onthe seeding or planting apparatus, to sort seeds according to measuredparameters related to viability so that seeds most likely to produceviable plants are planted and less viable seeds are used for otherpurposes. The present invention can be used to sort seeds according tosize for compatibility with planting devices. The invention can be usedto count seeds so that a specified number can be planted. The presentinvention can also be used provide a rapid stream of singulated seeds ofknown quality and number in a planting device. Because the number ofsingulated seeds per second provided by the present invention is muchhigher than prior art, a farmer can seed more acres per hour.

A mining operation produces ore, which is crushed to produce particlesof similar size and then smelted. Typically, only a small fraction ofthe ore is a useful mineral and the rest is rejected as slag. There is aconsiderable energy investment to melt rock that eventually ends up asslag. The present invention provides a means to improve the energyefficiency of a mining operation. The minerals present in each oreparticle vary and can be measured by various spectroscopic methods suchas x-rays, Raman, and infrared. Particles containing more than athreshold concentration of useful minerals can be directed to a smelterand particles containing less than a threshold concentration of usefulminerals can be directed to a refuse pile. The cost of melting therejected particles is saved.

The invention can be applied to sorting colloidal particles, which aretypically fabricated in a condensation process producing a distributionof sizes and shapes. The allowed electronic transitions in a metalliccolloid depend sensitively on the size and shape of the colloid. Theinvention could be used to sort colloidal particles on the basis of sizeand shape or on the basis of absorption spectrum into homogeneousclasses.

While the duct as described in some examples herein is typically achannel with upstanding sides formed in a disk, the duct can also becircular, oval, triangular or quadrilateral etc. or can be a partialtube that is generally C-shaped, V-shaped or L-shaped). The duct canalso be defined by a minimal two or three dimensional surface, orsurfaces defined by the points of contact imparting force on theparticles. The duct can also be an enclosed tube of many differentcross-sectional shapes such as circular, oval, triangular orquadrilateral.

Embodiments of the current art are capable of achieving a rate ofapproximately 100 kernels per second per channel with good accuracy andapproximately 200 kernels per second with poor accuracy.

The arrangement as described hereinafter may provide the objects toincrease the kernel rate, reduce the size of equipment, and reduce theenergy requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

FIG. 1 is an isometric view of a grain sorting apparatus showing aMethod of particle singulation according to the present invention.

FIG. 2 is a vertical cross-sectional view through the apparatus of FIG.1.

FIGS. 3A, 3B and 3C show vertical cross-sectional views through theseparating device of the apparatus of FIGS. 1 and 2.

FIG. 4 is a partial isometric view showing the shape of one of thegrooves or ducts of the apparatus of FIG. 1.

FIG. 5 is a vertical cross-sectional view a second embodiment of anapparatus using a method according to the present invention.

FIG. 6 is a schematic illustration of a stack of ducts for sizeseparation of particles for use in the apparatus of FIG. 1.

FIG. 7 is a vertical cross-sectional view a second embodiment of theapparatus using a method according to the present invention.

FIG. 8 is a plan view of the embodiment of FIG. 7 showing only one ofthe ducts.

FIG. 9 is a schematic illustration of a method including a series ofstages using the separation apparatus of FIG. 1.

FIG. 10 is a schematic illustration of another embodiment where theseparation system is used in a planting system for separation of viableseeds from less viable seeds and for counting the seeds so as to plantinto the ground a required counted number of viable seeds.

FIG. 11 is a schematic illustration of a method for carrying outdifferent actions on the particle using the separation apparatus of FIG.1.

FIG. 12 is a schematic illustration of the disk for use in the methodaccording to the present invention and showing different options forduct shape.

DETAILED DESCRIPTION

The apparatus for sorting particles based on a measurable parameter ofthe particles shown in FIGS. 1 and 2 comprises a supply conduit 10carrying particles to be sorted from a feed supply 10A which suppliesthe particles in a continuous stream for presentation through theconduit to a rotary body 11 rotatable around an axis 12. In theembodiment shown the rotary body is a flat disk with the axis 12arranged vertical so that the disk provides an upper horizontal surfaceonto which the particles 13 are supplied in the stream from the conduit10. The conduit is arranged at the centre of the disk so that theparticles are deposited onto the centre of the position where the diskis rotating but where there is little outward velocity. The kernelvelocity at this point is from the flow in the supply conduit 10. Thevelocity at a point on the disk is v=wr where w is the angular velocityand r is the radius. If kernels are deposited in a region where thechange in velocity is too high, they bounce and the flow is chaotic.Kernels are deposited in the central region to minimize the change invelocity.

On the upper surface of the disk forming the rotary body is provided aplurality of ducts 14 each extending from an inner end 15 adjacent theaxis outwardly to an outer end 16 spaced at a greater radial distanceoutwardly from the axis than the inner end. In this embodiment the outerend 16 of the ducts is arranged adjacent to but spaced inwardly from theedge 17 of the disk 11. In this embodiment each duct 14 extends from aposition closely adjacent the centre to the periphery 17 of the disk sothat the centre the ducts are arranged immediately side by side and theducts diverge outwardly so that at the outer end 16 they are spacedaround the periphery 17.

The inner ends 15 are thus arranged in an array adjacent to the axis sothat the supply conduit 10 acts to deposit the particles to be sorted atthe inner ends 15 of the ducts for entry of the particles to be sortedinto the inner ends. As the inner ends are immediately adjacent at thecentre of the disk, the particles there form a pile at the centre whichis automatically sorted evenly in to the open mouths of the ducts attheir inner ends. Assuming a continuous pile of the particles at thecentre, the rotation of the disk will act to evenly sort the particlesinto the individual ducts in a stream defined by the dimensions of themouth relative to the dimensions of the particles. At the outset of thepath along the duct, the particles will be immediately adjacent oroverlapping. However passage of the particles along the duct while theyare accelerated by the centrifugal forces will act to spread theparticles each from the next to form a line of particles with nooverlap. As the forces increase with increasing radial distance from theaxis 12, the particles will be increasingly accelerated and thus thedistance between particles will increase along the length of the duct.The kernels align with the duct axially in the first part of the ductand the kernel length defines an initial center to center spacing withsome variation due to differences in kernel size. The centrifugalacceleration is uniform at a given radius, but the frictional forces forgrain kernels vary by about 20%. The frictional forces scale with theCoriolis force=uN (u=coefficient of friction approximately 0.2-0.25,N=normal force to duct wall supplied primarily by the Coriolis force. Asset out above, the duct can be shaped to minimize the normal force andfriction by curving the duct along the line of net force (mentioned intext earlier). Conversely, the particle acceleration can be reduced bycurving the duct to increase normal forces, curving the duct to constantor even decreasing radius, or increasing the coefficient of friction ofa selected portion of a duct by changing the texture and/or material.

Selection of the length of the duct relative to the size of theparticles can be made so that the spacing between each particle and theparticle behind can be selected to be a proportion of the length of theparticles. In the example where the separator is used for seeds, theseparation between each seed and the next can be at least equal to thelength of the seeds and typically 1.5 or 2.0 times the length of theseed.

Thus the ducts are shaped and arranged so that the particles areaccelerated as they pass from the inner end to the outer end so as tocause the particles to be aligned one after the other in a row as theymove toward the outer end.

The outer ends 16 are arranged in an angularly spaced array at an outerperiphery of the rotary body so that the particles of the row ofparticles in each duct are released by centrifugal force from the diskoutwardly from the axis of the disk. The openings all lie in a commonradial plane of the disk. The ducts can be formed either as grooves cutinto the upper surface of a thicker disk or by additional walls appliedon to the top surface of the disk, or two-dimensional and/orthree-dimensional shaped guides.

An array 20 of particle separating devices 21 is arranged in an annulusat the outer edge 17 of the disk so that the individual separatingdevices 21 are arranged at angularly spaced positions around the disk.

Each separating device is operable to direct each particle into one of aplurality of paths as determined by operation of the separating devices.In the example shown the separating devices are arranged to direct theparticles upwardly or downwardly relative to the plane of the outlets16. As shown in FIG. 2 and the FIG. 3A the separating device 21 can takeup an initial intermediate or starting position where the particles arenot separated to one direction or the other. As shown in FIG. 3B, theseparating device can be moved upwardly so as to direct the particlesdownwardly into a path 22 for collection within a collecting chamber 23.Similarly when the separating device is moved to a lowered position asshown in FIG. 3C, the particles are moved upwardly over the top of theseparating device along a path 24 for collection within a chamber 25.The two paths 22 and 24 are separated by a guide plate 26 which ensuresthat the particles move to one or other of the chambers 23, 25.

In order to control the separating devices 21, there is provided ameasuring system generally indicated at 28 which is used to measure aselected parameter or parameters of the particles as those particlesmove from the end of the duct at the edge of the disk toward theseparating devices. The measuring devices are carried on a mounting ring28A.

The measuring system can be of any suitable type known in this industryfor example optical measuring systems which detect certain opticalcharacteristics of the particles to determine the particular parametersrequired to be measured. Other measuring systems can also be used sincethe type of system to be used and the parameters to be selected are notpart of the present invention.

In a typical example, the analysis of the particles relates to thepresence of degradation of the seed due to disease and this can often bedetected optically for example using the systems and disclosed in theprior U.S. Pat. No. 8,227,719 of the present inventor, the disclosure ofwhich is incorporated herein by reference or may be referenced forfurther detail.

Each separating device 21 is associated with a respective detectingdevice 28, which may include multiple detecting components, operable tomeasure the parameter of the particles and in response to the parametersmeasured by the associated detecting device, the respective orseparating device is operated to select the path 22 or the path 24.

It will be appreciated that the number of paths can be modified toinclude more than two paths if required depending upon the parameters tobe measured. Such selection to an increased number of paths can becarried out by providing subsequent separating devices 21 positioneddownstream of the initial separation. In this way one or both of thepaths can be divided into two or more subsidiary paths with all of theseparating devices being controlled by a control system 29 receiving thedata from the measuring device is 28.

The disk 11 thus has a front face 30 facing the supply conduit and theducts 14 lie in a radial plane of the disk and extend outwardly from theaxis to a periphery 17 of the disk 11.

As shown in FIG. 4, the ducts 14 form a standing wall 14A with an openface facing toward the supply conduit 10 and transversely across thedisk. The wall 14A defines a V-shaped cross-section with two sides 14Band 14C converging an apex 14E at which is provided rifling 14D. Howeverthe ducts may be closed at the top surface with only the mouth 15 andthe discharge end 16 open.

As shown in FIG. 1, the ducts 14 are curved so that the outer end 16 isangularly retarded relative to the inner end 15. This forms a sidesurface 14B of each duct as best shown in FIG. 4 which is angularlyretarded relative to the direction of rotation in the counter clockwisedirection as shown at D. This curvature of the ducts is arranged tofollow substantially the Coriolis and centrifugal forces so that theparticles follow along the duct without excessive pressure againsteither side wall of the duct. However the shape of the duct is arrangedso that the Coriolis forces tend to drive the particle against thedownstream side 14B of the duct 14. As shown in FIG. 4, the sidewall 14Bis inclined so that the force F on the particle pushes the particleagainst the inclined wall driving the particle toward the apex 14E ofthe duct 14. This acts to bring all the particles toward the apex 14E ofthe duct so the particles emerge from the disk at a radial plane of theapexes 14E of the ducts 14.

As shown in FIG. 4, the wall 14B includes rifling 14D formed as groovesor ribs running along the sidewall so that as the particles roll overthe surface from an upper edge of the surface to the bottom wall, theparticles are rotated around a longitudinal axis of the particles bothtending to align the particles with their longer axes longitudinal ofthe wall and also tending to spin the particles around this longitudinalaxis. The rifling grooves or ribs shown in FIG. 4 are segments ofgenerally helical paths that intersect the duct surfaces. The helicalpitch regulates the particle spin. In this way, as the particles slidealong the surface from the inlet 15 to the exit 16, the particles movetoward the apex of the surface and rotate around their axes to properlyorient the particles and the impart spin or rotation. As the particlesemerge from the discharge 16, these particles are therefore aligned in acommon radial plane, aligned with their longitudinal axes along the ductand with some spin as they emerge for better analysis of the particlesby the detection system 28. The rotation allows different surfaces ofthe particles to be presented to the detection system 28 to obtainaveraging of the surface characteristics. At the same time the particlesare presented in a common orientation.

As shown best in FIG. 1, the ducts 14 are immediately side by side atthe inner ends 15 adjacent the axis and increase in spacing toward theouter ends 16. At the inner ends 15 the ducts are immediately side byside so that the maximum number of ducts is provided by the maximumnumber of openings 15. The number of ducts can be increased, in anarrangement not shown, where the ducts include branches so that eachduct divides along its length into one or more branches.

In another arrangement not shown the ducts can be stacked one on top ofanother at the inner ends 15 to increase the number of the duct openingsat the inner end. That is for example, if three rings of ducts arestacked one on top of another, the total number of ducts can beincreased threefold. The ducts then are arranged in a common radialplane at the outer ends by the uppermost ducts moving downwardly whenspace becomes available at the outer edge to accommodate the three ringsof ducts in a common plane. In this way the outer ends 16 of the ductscan be arranged directly side by side at or adjacent the periphery 17 ofthe disk.

In the embodiment of FIGS. 1 and 2, the detection device 28 and theseparating device 21 are both located within the periphery 17 of thedisk. In this way the particles are guided as they pass from the outerend of the ducts to the array of separating devices.

In FIG. 5 is shown an alternative arrangement where the separatingdevices 21 are beyond the periphery 17 of the disk. In this embodiment,the particles travel along a trajectory determined by the angularvelocity of the disk 11 and the direction of the duct 14 at the outerend 16. The associated detecting devices 28 are located relative to theseparating device 21 to act on the particle in its trajectory. That is,the trajectory is arranged in the free space between the outer periphery17 and the separating device 21 so that a particle exiting the dischargeend 16 of a duct travels past one of the detecting devices 28 dependingupon its position of release and from that detecting device the particlemoves to an associated separating device 21 which acts to separatedepending upon the analysis carried out by its associated detectingdevice 28. It is necessary therefore the trajectories are consistent andensure that the particle that is detected is moved to the requisiteseparating device.

If required there is provided a movable guide member (not shown) at theouter end of each duct for changing the trajectory with the guide memberforming a guide surface which can be rigid or flexible which changesorientation in an angular direction to direct particles to the nearestdetector and associated separator as the disk and the ducts thereonrotates and moves from one detector to the next.

In another arrangement, not shown, instead of using the particletrajectory to control movement of the particle past the requireddetecting device and associated separating device, each separatingdevice 21 is associated with a guide channel into which the particleenters when it is released from the outer end 16 and the associateddetecting device 28 acts on the particle in the guide channel.

In another arrangement not shown, both the detecting devices and theseparating devices are mounted on the disc for rotation with the ducts.In this way the separating device is directly associated with arespective one of the ducts to ensure that the particles travelling inthe duct move past the associated detecting device and from thatdetecting device directly to the separating device to ensure accurateseparation without the possibility of errors caused by differences intrajectory of the arrangement of FIG. 5. Again the separating devicesact to separate the particles, depending upon their detectedcharacteristics in to a path or separated by a guide. In thisarrangement the path is through an opening in the disk.

As best shown in the FIGS. 3A, 3B and 3C, each separating devicecomprises a separating head 40 having a front edge 41 lying generally ina radial plane of the disk 11 so that particles released from the outerends 16 move toward the front edge 41. The separating head 40 includesthe inclined guide surfaces 42 and 43 on respective sides of the frontedge 41. In this way the separating head 40 is generally wedge shaped.The separating head is mounted on a lever 44 mounted inside a tube 45 sothat the lever and the actuating mechanism for the lever are protectedinside the tube which is located behind and protected by the separatorhead. An actuator 46 is provided for moving the front edge 41 betweenfirst and second positions above and below the radial plane 47 definedby the path of the particle 13. Thus in FIG. 3A a central and neutralposition is shown. In FIG. 3B the front edge 41 has moved upwardly whichis arranged to direct the particle to a side of the radial plane belowthe radial plane. In the position shown in FIG. 3C, the front edge ismoved downwardly to a second side of the radial plane and is arranged todirect the particle to the first or upper side of the radial plane. Thismovement of the wedge shaped head and its front edge requires littlemovement of the front edge 41 and uses the momentum of the particleitself to cause the separation simply by the particle sliding over theguide surfaces 42 and 43. The separation head therefore does not need tomove into impact with the particle or to generate transverse forces onthe particle since the head merely needs to move into position allowingthe particle to generate the required separation forces.

In view of the provision of the lever, the actuator 46 required togenerate only small distance movements and hence can be moved by piezoelectric members. Alternatively the movements can be carried out by asmall electromagnetic coil. This design allows the use of componentswhich can generate the necessary high-speed action to take up the twopositions of FIGS. 3B and 3C sufficiently quickly to accommodatehigh-speed movement of the particles. As shown the actuator 46 islocated outward of the separating head and lies in a radial plane of theseparating head.

The arrangement of the present invention therefore provides a system forseparation of the particles, for example kernels, where the particlesare supplied in a feed zone and are separated by the ducts and the inletof the ducts so as to form a plurality of streams of the particles.

The flow rate of the feed tube 10 is determined by its narrowest waistand this can be controlled to provide a suitable flow rate for theparticles. The kernels fill the central zone at the centre of the diskand flow radially into the channels in an alignment zone. The removalrate of the particles along the ducts is arranged by selection ofdimensions and rotation rate to be equal to the feed rate supplied bythe feed duct 10. The flow satisfies the continuity equation P1V1=P2V2where P1 and P2 are the kernel number densities and the V1 and V2 arethe kernel velocities. The average centre to centre separation betweenkernels is proportional to V.

A second constraint is provided by the width of the ducts 14 where thechannel width is selected so as to avoid kernel blockages. Thus thechannel width is preferably greater than the kernel length to avoid ablockage. Where the channel width is greater than 1.5 times the kernellength, the kernels can flow without constriction. In this way thenumber of channels times the width of the channel may be approximatelyequal to the feed tube diameter. However, the channels do not need tostart at the feed tube diameter. In general, there can be a flat zonewith diameter greater than that of the feed tube diameter before thestart of the channel.

A further constraint relates to the allowable difference in velocitybetween the disk 11 proximate to the feed duct 10 and the feed duct 10itself. The difference in velocity between the feed and the disk at thefeed zone radius must be less than 2 m/s and preferably less than 1 m/sfor wheat kernels. The allowable difference in velocity in generalvaries with the type of particle to be singulated. Kernels with largeDelta v bounce up from the disk. A larger velocity can be tolerated inan arrangement where a cover is provided over the disk at the centralfeed location. A small initial velocity from the feed tube is desirableto aid movement from the feed zone to the alignment zone. If the initialvelocity is too large, the kernels bounce up. The initial velocity isregulated by the vertical separation between the feed tube and the disk11. A central cone may be provided to assist in the directing thematerial outwardly at the center away from the axis.

In the alignment zone provided by the ducts, kernels flow from the feedzone into the channels. The flow is promoted by centrifugal force whichin this zone is close to 1G. Initially the kernels are close packed. Askernels gain radial velocity, the average separation increases and theCoriolis force, typically 1 to 3G, proportional to the radial velocityis exerted on the kernels. The Coriolis force causes kernels to alignend-to-end along the downstream or trailing side wall of the channel orduct. The kernels experience a drag force due to friction from the sidewall proportional to the vector sum of gravity and Coriolis forces. Thecoefficient of friction is minimized or reduced by fabricating the diskfrom a smooth abrasion resistant material. Preferably the sidewalls ofthe ducts are curved or inclined in the vertical direction so that thekernels move into a common radial plane in the Z direction due to theCoriolis force along the sidewall of the channel.

In the acceleration zone the spacing between kernels increases as thekernels are accelerated by centrifugal force. As shown the ducts arecurved so that the Coriolis force also contributes to kernelacceleration. The sidewalls of the channel are manufactured from asmooth hard material to minimize the friction and wear. The net force oneach kernel is typically much greater than 1G and increases rapidly withradial displacement. In one example, in a disk of 220 mm diameterspinning at 400 rpm the maximum force is approximately 44G. Aerodynamicdrag forces on the kernels become important with increasing velocity,ultimately setting a terminal velocity between 8 m/s and 9 m/s. Highervelocities can be achieved if the ambient pressure is lowered at thedisk by a vacuum pump or the region surrounding the disk is filled witha gas less dense than air such as helium. A difference in pressure canbe used to increase the flow rate in the feed tube while the same timeincreasing the terminal velocity. Ignoring frictional forces, the finalvelocity of the kernel leaving the peripheral edge 17 of the disk isequal to the angular velocity of the disk times the disk radius.

In respect of the rate of kernels passing the detector 28, it isdesirable to have a centre to centre separation sufficient to allowejection of one kernel without influencing the trajectory of thefollowing kernel. By the continuity equation given above, a separationof two wheat kernel lengths corresponds with a kernel rate ofapproximately 80 kernels per second for every 1 m/s of kernel velocity.

The detection of the characteristics of the kernels is not a part of thepresent invention and hence is not described in detail. Many differentsensing systems can be used using different techniques and the differentcharacteristics of the particle.

In one example an optical system is used where a sampling region isilluminated with suitable light characteristics. Reflected light isreceived from the particle under investigation as the particle travelsthrough the sampling region. The reflected light can be analysed fordifferent characteristics at different wavelengths. The analysis can becarried out by a spectrometer.

As described above, the kernels are deflected by a mechanical lever. Inone embodiment, the mechanical lever may be attached to a rotary voicecoil. In a preferred embodiment, the mechanical lever is driven by apiezoelectric transducer. In one embodiment, a piezoelectric stackproduces a small displacement which is amplified by leverage. In apreferred embodiment, the piezoelectric transducer is a bimorph. Thewedge head 40 with an apex angle of between 20 and 45 degrees is mountedon the end of the bimorph. More preferably the apex angle is between 30and 35 degrees. Kernels are directed toward the front edge of the wedgeshaped head by the singulation apparatus. When voltage is applied to thebimorph, the wedge is deflected away from its central resting position.If the sign of the voltage is reversed, the direction of deflection isreversed. A bimorph 40 mm long can produce about 2 mm of displacement. Abimorph can be driven significantly faster than other types of ejectors.A shorter response time at the ejector allows a higher kernel rate.

Turning to FIGS. 7 and 8, there is shown a further embodiment includinga disk 300 driven by a motor 301. A feed conduit 302 supplies theparticulate material along a path 303 to a feed location 304 where theparticular material is dropped onto the upper surface of the disk 300. Acentral cone or dome portion 305 is located directly under the conduit302 so as to assist in spreading the material outwardly into theplurality of ducts 306, 307, the number of which of course is variablefrom minimum of one up to the maximum number which can be obtainedwithin the area available. Particularly when there is a large number ofducts, there is provided a gate 308, 309 each of which is positioned outthe inlet to the respective duct so as to control the flow of theparticular material into the ducts. In this way when the quantity offeed material is relatively low, some of the ducts can be closed off byoperating an actuator 310 driving the respective gate.

Each duct is formed by a channel with two generally upstanding sidewalls311 and 312 between which the particles pass. These may be vertical, butmore likely have “inclined” sidewalls as described previously. Also,depending on the item being sorted and the geometry of the rotary body,this duct can be a tube (circular, oval, triangular or quadrilateraletc.) or a partial tube i.e. C-shaped, L-shaped, V-shaped, or a minimaltwo-dimensional and/or three-dimensional shape following the path(s)where force is exerted on a particle by the duct.

Each duct such as the duct 307 shown in FIG. 8 includes a first portion313, a second portion 314 and the third portion 315 at spaced positionsalong the length of the duct leading to a discharge mouth 316 at the endof the duct opposite from the gate 309. The first portion 313 of theduct is shaped and arranged so as to provide acceleration of theparticles after entering through the gate 309 so as to separate theparticles of each from the next longitudinally along the length of theduct portion.

The second duct portion 314 includes one or more sensors 317, 318, 319at spaced positions along the length of the duct portion 314. Thesensors can be used to measure different characteristics of theparticles passing through the duct portion 314 so that a control device320 which receives the signals from the sensors can direct theseparation system for separating the particles within the duct.

The second duct portion 314 is shaped and arranged so as to provide areduced acceleration of the particles within the second duct portion.Preferably the arrangement is such that in the second duct portion thereis a very low or zero acceleration of the particles so that theymaintain a nearly constant velocity through the second duct portion asthey pass the sensors. This can be achieved, for example by setting thefriction in the second duct region to balance centrifugal acceleration.Alternately or in combination with friction, the centrifugalacceleration can be reduced by arranging the second duct portion along acurve of nearly constant radial distance from the axis of rotation.

The third duct portion 315 acts as a separation system in that ductportion 315 is pivotal about a mounting pin 321 so as to move thedischarge end 316 between at least two separate positions. In theposition shown on the right end at the duct 307, the discharge opening316 lies in the same plane as the disk and directs the particles exitingthis discharge opening into a first channel 322 for collection as a setof the particles having a first characteristic measured by the sensors.A second channel 323 is provided for receiving the particles in thesecond position of the duct portion 315 as shown at the left end of FIG.8 in respect of duct 306.

Thus it will be noted that the duct portion 315 is moved between thefirst and second positions of the channels 322 and 323 by an actuator324 which lifts the discharge end 316 upwardly and downwardly betweenthe channels 322 and 323. Typically the actuator 324 is anelectromagnetic voice coil which provides sufficient force and movementto lift the duct portion 315 between the two positions.

As shown, in this embodiment the third duct portion 315 forms a part ofthe main duct 306 or 307 and is carried on the disc 300 for rotationtherewith.

The third duct portion 315 as shown is also shaped differently from thefirst and second duct portions in a manner which causes a decelerationof the particles passing therethrough. Thus the particles as they emergefrom the discharge end 316 are at a velocity which is reduced relativeto the velocity during the measurement stage so as to reduce thepossibility of impact damage after the particles leave the dischargeend. It should be noted that the desired velocity profile through theduct is depends on the material properties. For some materials, thethird duct portion may be shaped to provide an increase in velocity. Asan alternative, the third duct portion can be replaced by an inclinedgate which can be rigid but more preferably is flexible and curved so asto apply lower redirecting forces on the particles.

In addition to or instead, the particles within the duct portion 314 canbe decelerated by an airstream directed along the duct tending to slowthe movement of the particles. Again this is used to decelerate theparticles to prevent or reduce impact damage from when the particlesleave the opening 316.

In addition to or instead, the particles within the duct portion 314 canbe decelerated by a water curtain such as a waterfall or meniscus aspreviously described.

In addition to or instead, impact damage can be reduced by providing aresilient layer 326 on the surface of the channel 322, 323 against whichthe particles impact when they leave the discharge opening 316. In oneexample the layer 326 is a resilient material such as rubber. In anotherarrangement, impact damage can be reduced by inclining the surfaceagainst which the particles impact.

In the arrangement of FIG. 1, the separator 21 includes a cover portion21A which forms a closed channel through which the particle selected forthe path 24 passes. This channel can include impact surfaces and/orother components which act to cause deceleration. Also in FIG. 1, thematerial exiting from the periphery 17 of the disk is collected in acollector channel 98 which contains a suitable deceleration material 99as described herein.

All of the methods mentioned pertaining to deceleration whileapproaching the separation system are potential techniques that could beused to decelerate the particles after separation. Deceleration afterseparation will be very important depending on what is being sorted.

Thus in this embodiment, the end portion of the duct is mounted on ahinge which enables the end portion of the duct to slope either up ordown so that exiting the duct are deflected either up or down. The endportion of the duct is attached to an actuator which may be a piezoactuator, a rotary voice coil or other suitable actuator. The advantageof this method is that the angular displacement of the end portion tothe duct can be varied based on kernel quality characteristics to sortkernels into a plurality of output streams with a single device.

In the ejector, the kernel travels toward the ejector which consists ofthe wedge shaped head 40 mounted on the end of a piezo bimorph mountedin the tube. The position shown in FIG. 3A shows unpowered piezo bimorphin which a kernel has equal probability of being deflected into theupper bin or the lower been separated by the divider. The position shownin FIG. 3B shows position of ejector when +100 V is applied to piezobimorph and kernels are deflected into the lower been. The positionshown in FIG. 3C shows position of ejector when −100 V is applied topiezo bimorph and kernels are deflected into the upper bin.

The separator system as described and illustrated herein can be usedwith systems where there is no specific measurement of a parameter ofthe particle as the features of the separating device can be used inother fields.

As shown in FIG. 10, there is shown a seeding system generally indicatedat 400 including a seeding tool bar 401 on which is mounted a series ofindividual planting devices 402. Each planter 402 is fed with seeds by atransfer duct system 403 which is fed with seeds from a separator 404generally as described above where a hopper 405 supplies seeds to theseparator.

Thus the measurement and separation system of the present invention isused on the seeding or planting apparatus 400 to sort seeds according tomeasured parameters related to viability so that seeds most likely toproduce viable plants are planted and less viable seeds are used forother purposes. The present invention can be used to sort seedsaccording to size as detected by a sensor 406 for compatibility withplanting devices. The sensor 406 can be used to count seeds so that aspecified number can be planted or packaged. The arrangement alsoprovides a rapid stream of singulated seeds separated by the separator407 of known quality and number in a planting device. Because the numberof singulated seeds per second provided by the present invention is muchhigher than prior art, a farmer can seed more acres per hour.

As shown at 408, a portion of the duct proximate to the measurementdevice 406 is comprised of a transparent material 409.

Also as shown at 410 a measurement devices is located proximate to a gap411 in the duct gaps to measure different parameters of the particlewith a view unobstructed by the walls of the ducts. In this arrangementthe duct portion 412 is substantially parallel to the average velocityvector of the particles at the location of the gap 411 to minimizeperturbation of particle flow along the duct.

As shown in FIG. 6, one duct is shown which basically has the V-shapedprofile shown in FIG. 4. That is the duct 14 is shaped such that theacceleration causes the particle to move against the walls 14B, 14C ofthe duct where the wall is V-shaped to confine the particle to a base ofthe V-shape.

The wall 14 includes one or more openings 14G at the apex such that theparticles 13 run on the walls 14B, 14C but components 13A smaller thanthe particles are separated from the particles by release throughopenings 14G. In the embodiment shown the openings 14G are in the formof a generally continuous opening along the apex. Thus each ductincludes an associated second duct 14S parallel to the duct 14 intowhich the separated smaller components enter. This is then followed by athird duct 14T which again takes yet smaller particles 13B Thus there isa stack of such ducts 14, 14S, 14T so that the particles are separatedby size from the first duct 14.

Also as shown schematically in FIG. 10, the separation of the particlesat separator 407 is carried out using electrostatic forces where theparticles are charged differentially according to selected parametersand then passed through a field 412 so that the differential chargingcauses the particles to divert to different paths.

FIG. 9 is a schematic illustration of a method including a series ofstages using the separation apparatus of FIG. 1.

As shown, an initial singulation and separation process indicated at 500based on particle size communicates the separated materials in paths 501and 502. In path 501 the particles are subject to a coating step 503followed by a UV curing step 504. In path 502 the particles are subjectto a UV sterilization step 505 followed by an antibody application step506.

At the end of path 501, a second separation step 507 based on sizepasses the particles accepted through a path 508. In path 508 theparticles are subject to a UV sterilization step 509 followed by anantibody application step 510. At the end of path 508, a furtherseparation step 511 selects the particles for accept or reject paths.Similarly at the end of path 502, a further separation step 512 selectsthe particles for accept or reject paths.

FIG. 11 is a schematic illustration of different actions on the particleusing the method of the present invention. That is in these cases thesigulation method is used not for sorting as described above but insteadfor various operations such as counting, coating, sterilization andothers.

FIG. 12 is a schematic illustration of a disk of the apparatus of FIG. 1showing different options for duct shape. In each duct, the angle of theduct to a radius of the disk causes different effects of acceleration,no acceleration (constant velocity) and deceleration. That is in duct141 the particle as it moves outwardly is subjected to increasingacceleration. In duct 142 the particle as it moves outwardly issubjected to acceleration followed by constant velocity followed byfurther acceleration. In duct 143 the particle as it moves outwardly issubjected to acceleration followed by constant velocity followed bydeceleration. In duct 144 the particle as it moves outwardly issubjected a variable velocity profile.

The invention claimed is:
 1. A method for separating particlescomprising: carrying particles to be sorted in a supply conduit;rotating a rotary body around an axis of the rotary body; the rotarybody defining at least one duct extending from an inner end adjacent theaxis outwardly to an outer end spaced at a greater radial distanceoutwardly from the axis than the inner end; forming the particles fromthe supply conduit into a stream of the particles in a row in said atleast one duct; locating a particle separating device at the streamoperable to direct each particle into one of a plurality of paths;wherein the separating device comprises: a separating head having afront edge lying generally along the stream so that particles in thestream move toward the front edge; and an actuator for moving the frontedge between a first position on a first side of the stream, arranged todirect the particle to a second side of the stream, and a secondposition on the second side of the stream, arranged to direct theparticle to the first side of the stream; wherein the separating head isarranged in a radial plane of the axis of the rotary body and the firstand second sides are arranged on respective sides of the radial plane.2. The method according to claim 1 wherein said at least one duct liesin said radial plane.
 3. The method according to claim 1 wherein theseparating head includes inclined guide surfaces on the first and secondsides of the front edge.
 4. The method according to claim 1 wherein theseparating head is generally wedge shaped.
 5. The method according toclaim 1 wherein the actuator is moved by piezo electric members.
 6. Themethod according to claim 1 including rotating the rotary body at anangular velocity which generates a centrifugal force on the particleswhich overcomes a friction force on the particles caused by contact ofthe particles with the duct thus causing the particles to be acceleratedas the particles pass from the inner end to the outer end and causingthe particles to be separated each from the next by a space by saidacceleration caused by the centrifugal force in said at least one ductand causing the particles to be aligned one after another in a row insaid at least one the duct as the particles move toward the outer end.7. The method according to claim 1 wherein said at least one duct has awall which is segmented with at least one gap between segments of thewall or between separate segments of said at least one duct.
 8. Themethod according to claim 1 wherein a surface of said at least one ductincludes rifling for engaging and rotating the particles in said atleast one duct.
 9. A method for sorting particles comprising: carryingparticles to be sorted in a supply conduit; forming the particles fromthe supply conduit of massed particles into a stream of the particles ina row; locating a particle separating device at the stream operable todirect each particle into one of a plurality of paths; wherein theseparating device comprises: a separating head having a front edge lyinggenerally along the stream so that particles in the stream move towardthe front edge; and an actuator for moving the front edge between afirst position on a first side of the stream, arranged to direct theparticle to a second side of the stream, and a second position on thesecond side of the stream, arranged to direct the particle to the firstside of the stream; wherein the method includes rotating a rotary bodyaround an axis; the rotary body defining at least one duct in which saidstream is formed extending from an inner end adjacent the axis outwardlyto an outer end spaced at a greater radial distance outwardly from theaxis than the inner end; feeding the massed particles at the inner endof said at least one duct; the inner end being arranged adjacent theaxis so that the supply conduit acts to deposit the particles at theinner end of said at least one duct for entry of the particles into theinner low velocity end and for separation of the stream of particles inthe conduit into separate ones of said at least one duct; rotating therotary body around an axis at an angular velocity which generates acentrifugal force on the particles in said at least one duct whichovercomes a friction force on the particles caused by contact of theparticles with said at least one duct thus causing the particles to beaccelerated as the particles pass from the inner end to the outer endand causing the particles to be separated each from the next by a spaceby said acceleration caused by the centrifugal force in said at leastone duct and causing the particles to be aligned one after another in arow in said at least one duct as the particles move toward the outerend.
 10. The method according to claim 9 including aligning longitudinalaxes of each of the particles one behind another along the side wall ofsaid at least one duct by applying a friction force on the particlesrelative to the side wall of said at least one duct.
 11. The methodaccording to claim 9 wherein said at least one duct has a wall which issegmented with at least one gap between segments of the wall or betweenseparate segments of said at least one duct.
 12. The method according toclaim 9 wherein a surface of said at least one duct includes rifling forengaging and rotating the particles in said at least one duct.
 13. Themethod according to claim 9 wherein the friction force on the particlesrelative to a side wall of the duct causes the particles to align withlongitudinal axes thereof aligned along the side wall of said at leastone duct.
 14. The method according to claim 9 including aligninglongitudinal axes of each of the particles one behind another along theside wall of said at least one duct by applying a friction force on theparticles relative to the side wall of said at least one duct.
 15. Themethod according to claim 9 wherein the actuator is moved by piezoelectric members.
 16. A method for separating particles comprising:carrying particles to be sorted in a supply conduit; rotating a rotarybody around an axis of the body; the rotary body defining at least oneduct extending from an inner end adjacent the axis outwardly to an outerend spaced at a greater radial distance outwardly from the axis than theinner end; forming the particles from the supply conduit into a streamof the particles in a row in said at least one duct; locating a particleseparating device at the stream operable to direct each particle intoone of a plurality of paths; wherein the separating device comprises: aseparating head having a front edge lying generally along the stream sothat particles in the stream move toward the front edge; and an actuatorfor moving the front edge between a first position on a first side ofthe stream, arranged to direct the particle to a second side of thestream, and a second position on the second side of the stream, arrangedto direct the particle to the first side of the stream; rotating theparticles in said at least one duct by providing rifling in said atleast one duct engaging the particles as the particles move along saidat least one duct; and aligning longitudinal axes of each of theparticles one behind another along the side wall of said at least oneduct by applying a friction force on the particles relative to the sidewall of said at least one duct.
 17. The method according to claim 16wherein said at least one duct lies in a radial plane of the axis of therotary body and wherein the separating head is arranged in the radialplane and the first and second sides are arranged on respective sides ofthe radial plane.
 18. The method according to claim 17 wherein theseparating head includes inclined guide surfaces on the first and secondsides of the front edge.
 19. The method according to claim 18 whereinthe separating head is generally wedge shaped.